Questions tagged [odds-ratio]

A measure of association between two binary variables equal to the odds of a 'positive' outcome in 1 variable divided by the odds in the other. The OR ranges (0, infinity). It has a strong connection to logistic regression.

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48 views

Why is odds ratio used when interpreting logistic regression?

I am fairly certain when interpreting logistic regression output, the odds ratio should be used instead of the estimated coefficients; however, I am unable to figure out why this is the case. So my ...
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Converting an effect on complementary-log scale to odds ratio

I'm trying to figure out how "an effect of treatment (beta) = 0.5 on complementary log scale" translate into an odds ratio (with baseline risk = 0.35)... I found the clog-log h(t) = log(-log(1-h(t))) ...
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32 views

Why is my meta analysis OR and 95% CI less precise than my study results?

I am trying to perform a simple weighted average meta analysis of 2 odds ratios from 2 studies (I will be adding more studies when I get the results). However, when I meta analyse using the METAFOR ...
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Can you use multiple reference groups in a single logistic regression?

When performing logistic regression for a binary categorical variable (i.e. 'gender', being Male or Female in this simple ...
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How can one define the power of a randomized clinical trial?

The statistical power of a study is a measure of the ability of a randomized clinical trial (RCT) to detect a difference statistically significant of the treatment effect in the treatment arms. How ...
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What's the interpretation of the ratio of the odds ratio between the experimental and the control arm?

Table 1 of this article show the associations between the outcome and variables, the authors presented the OR_ctr in control arm and ...
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How can an odds ratio of 1.757 make sense for this continous variable?

An odds ratio of 1.757 for a continuous variable means that the odds increase by 75.7% with every unit increase. But for two unit increases that would make the increase of the odds >150%. Am I correct ...
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Conditions when the log of Relative Risk is approximately Normal

Under what conditions is the log of RR (or OR) approximately Normally distributed? Sources would be very much appreciated - wikipedia for example just states the SE formula but provides no information ...
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How to generate Odds Ratio table using Python? [closed]

I am working on a binary classification problem and am trying to do univariate analysis to get their p-values and risk ratios. ...
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34 views

Interpretation of the beta regression coefficients with logit link used to analyse percentage 0-100%

I would like to model a percentage response. This percentage is not quite a probability or ratio of 2 quantities. It is reported by customers and expresses they pleasure of shopping. They report it ...
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Interpreting the Odds Ratio of a logistic regression model

I'm currently working on building a logistic regression model with the aim of predicting whether a given stock index will go up or down the following day. The table below shows the 3 models I've ran ...
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1answer
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how I can report the result of binary logistic regression?

We are conducting research to examine a relationship between some triggers and migraine with aura. therefore, we conduct logistic regression for the significant relationships to know the adjusted odd ...
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Degree of Confidence for an Odd's Ratio 2014 Cochrane Review Bronchiolitis

Given the following: Odds Ratio (M-H, Fixed, 95% CI) 0.75 [0.46,1.21] Is there a degree of confidence with which I can say that the true ratio is less than 1? Here is the background: The 2014 ...
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Categorization of continuous predictor in logistic regression

I have one continuous variable GENETIC SCORE and one binary variable HEALTH (case vs control i.e. 0/1). I want to fit a log regression model to this data to get the odds ratio for different percentile ...
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Double odds of one outcome, what should happen to the other outcomes?

When you have a binomial outcome, doubling the odds of one outcome halves the odds of the other outcome. E.g. if I have a weighted coin that doubles the odds of heads, it halves the odds of tails. If ...
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Need help understanding logistic regression output with seemingly contradictory results after swapping reference group

Some background, each of these predictors are 0, 1 one-hot-encoded categories that represent items in a basket (think e-commerce). Each observation can have multiple 1s. For instance, a single ...
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How to calculate individual odds ratio with genotype data?

I notice that one of the resolution isglm(outcome~ snp , family = binomial), but what is the data format of snp in the code?
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Is it possible to calculate odds ratio(95% CI) for only control group?

The original data contains scores of case/control group. The score is the number of risk alleles multiplied by the regression coefficient for SNP. So in the data, case samples have higher score than ...
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Is a super high odds ratio unusable?

So I've been working on a logistic regression model, and all has been going well for the most part. However, I just started analyzing the results and trends of the model, and one particular odds ratio ...
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Interpreting interaction odds ratios in ordinal regression

I have run an ordinal regression in R using polr from the MASS package. I'm trying to interpret an interaction. Both predictors are categorical. Here is an example: Predicting success in the job ...
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What is the relationship between two exposure-outcome odds ratios (ignoring pairing)?

Consider a sample of case-control pairs (who are, by definition, outcome- discordant) who are also exposure-discordant. Without loss of generality let (i) the first member of each pair be the index ...
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Estimating/translating odds ratio for different percentile intervals

I have a question regarding a translation in odds ratio curve OR(x). More specifically, let's say we have an OR(x) which we get using logistic regression. We look at the interval bounded with 25% and ...
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Vertical translation of independent variable vs OR and independent variable vs RR curve

i have been trying to predict risk of developing a cancer from genetic data. At the end I plotted a curve, that shows odds ratio (OR) and relative risk (RR) as a function of polygenic risk score (PRS) ...
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What is the difference between standardized mortality ratio (SMR) and odds ratio (OR) from age matched case and controls?

My question refers specifically to comparisons of chronic diseases, say heart failure (HF), between a specific group of interest (eg, diabetics) and a reference group (non-diabetics). SMR is the ...
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Odds Ratio Interpretation and Predicted Probabilities

I am conducting research on the association between smoking and Tuberculosis (TB), and I need to clarify what the odds ratio is telling me. I am getting the Odds Ratio value from the table of a ...
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1answer
46 views

Generate odds ratios across deciles / quantiles of an indpendent variable

With reference to the following figure from Bellomo et al., 2011: How exactly are the odds ratios across the deciles 'referenced against the 4th decile' calculated? My initial impression is that a ...
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Derivation of variance of Odds Ratio in a 2x2 table

Assuming that the elements of a 2x2 table (a,b,c,d) are binomial in distribution with a being $Bin(n_1,p_1)$ and c being $Bin(n_2,p_2)$. How can we show that $\hat {var(logOR)} = \frac 1 a + \frac 1 b ...
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How to interpret odds ratio with continuous independent variable (%) that have categories in different columns?

I am using a logistic regression to model a 0/1 event with community characteristics as being my explanatory variables but my data structure is different making the interpretation hard. My unit of ...
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Interpreting Odds Ratios for non-binary outcomes [duplicate]

I'm looking to interpret odds ratios with a quaternary outcome. Specifically, I'm trying to predict students' ratings of fairness (ordinal from Likert scale, 0-3) on a particular exam, based on the ...
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1answer
106 views

Interpreting odds ratios in ordinal logistic regression

I am trying to predict exam performance (below, average, above) based on whether participants attended a revision class. I am analysing my data in R using a proportional odds logistic regression. I am ...
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1answer
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When Can I say odds ratio is important to analyze my data

Lets say in my data if I generate odds ratio between 2 variable A and B and get that the odds ratio is 2-5 is that a good thing to dive deep further or should I move to other relations .
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High odds ratio for composite score created by ridge regression

This question is a follow up to one of my previous questions asked on this site. The goal was to create a composite score for biomarkers related to a binary outcome and then use that in a regression ...
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160 views

Use example to explain odds ratio to layperson audience

I found an example of how to express odds-ratios in plain english. Here is the link http://www.pitt.edu/~bertsch/risk.pdf It says: How does one express an OR of 0.15 in plain English. Had this ...
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Interpreting a very small odds ratio when the Fisher's exact test is significant

I'm having a hard time interpreting odds ratios (OR) for a 2x2 contingency table. ...
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76 views

Group level effects (odds ratio) - dummy coding vs. effect

I ran a logistic model in R's brms, with a categorical variable (condition) with two levels as predictor. When interpreting the ...
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1answer
44 views

Log odds Standard Error

I am reading a paper on how the authors calculate the variance/standard deviation of what appears to be log(odds). The paper is a medical paper (Discontinuation of Oral Antivirals in Chronic ...
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32 views

Correct interpretation of odds ratio

I am wondering what the correct way of interpreting an odds ratio is. For example, suppose we have that the probability of success is $p=0.8$. Then, the odds ratio is: $$ \frac{p}{1-p} = \frac{0.8}{0....
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Odd Ratios Change After Including Other Independent Variables… What does that exactly mean?

I am currently writing my master's thesis and I want to identify whether Austrians living in Vienna are more likely than immigrants in Vienna to become self-employed. In order to find out whether this ...
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How to interpret multinomial regression results? [duplicate]

I want to investigate the relationship between stock traders' past success rate (i.e. the number of total winning trades divided by the total trades executed) on the status of their current trading ...
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1answer
28 views

When to exponentiate: the mean of the chain or at every step in the chain?

I am interested in when it is best to exponentiate a difference in log-odds Here is a sample problem in the stan language, three groups of forty binary observations, group 1 with hit probability = 0....
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Interpreting odd's ratios

If A is a binary faction (1 A and 0 not A) and if the odds ratios of A to B is (say) 1.2409 (24 percent or e ^ 0.2158). Then is the odds ratio of B to A 76% or 1 – 0.24?
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Odds ratio confidence intervals and p-values suggest different conclusions in a binary logistic mixed-effects model (glmer)

I am running a generalized linear mixed-effects model in R using the glmer function of lme4. The outcome variable is trial-level accuracy in a task (incorrect trials are 0, correct trials are 1), and ...
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Effect size in linear mixed models

Thank you for reading this question. I know there have been a few discussions regarding this topic, but I couldn't get a satisfactory answer. So here is my question, with some details in the ...
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Baffled by inconsistency between 95% CI for OR and p-value

I am using logistic regression to model the effect of two production variables on the occurrence of tuberculosis. My independent variables are A (farm size: 0 for small, 1 for large) and B (cattle co-...
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Ratio as independent variable for logistic regression

I am trying to model the association between "previous 2 year history of no shows for consult (independent variable)" with current no shows (dependent variable) using a logistic regression model. The ...
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1answer
75 views

Convert odds ratio back to logit - logistic regression

I'm attempting to convert odd's ratios reported in results back to their original logit form. From what I've gathered, the appropriate formula to do so is: ...
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240 views

Does the “divide by 4 rule” give the upper bound marginal effect?

In the logisitic regression chapter of "Data Analysis Using Regression and Multilevel/Hierarchical Models" by Gelman and Hill, The "Divide by 4" rule is presented to approximate average marginal ...
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Interpreting infinite odds ratio and confidence interval from Fisher's test

I've performed a two-sided Fisher's exact test on the following data, and the results include Infinity for the upper confidence interval and odds ratio. Are these results erroneous, and if not how do ...
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Interpretation of chisquare and odds ratio

I am studying te association between variables and used the chisquare test and the odds ratio of fisher exact test. I would like to know the exactly interpretation that i can do. The main variable is ...
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Multiple risk ratio analysis or single multiple logistic regression for survey

I was asked by a doctoral student to analyze the answers to an old questionnaire her lab has and would like to publish the results of. There are a few questions with regards to animal care and disease ...